An oven generally includes an oven cavity configured to receive food articles for cooking. The oven also includes a heating element, which can be an electric resistance element or a gas burner, for generating heat energy to cook any food items placed within an oven cavity. Some ovens may include a fan for forcing movement of heated air within the oven cavity, and those ovens are commonly referred to as convection ovens.
Convection ovens have been the workhorse in commercial kitchens for many decades. Commercial convection ovens generally come in two sizes, namely, full-size and half-size. Full-sized commercial convection ovens are designed to fit within the space of an industry standard footprint, which is approximately 40 inches wide by 40 inches deep, made available for full-sized convection ovens in most commercial kitchens. The oven cavity of full-sized commercial ovens are also dimensioned to accept industry standard full-sized cooking trays, which are approximately 26 inches wide by 18 inches deep. The height of the cook cavity is typically about 20 inches, which is capable of being configured to allow for multiple rack heights, such as 11 possible rack heights, to accommodate the height of various foods that can be cooked in a convection oven. For example, only 2 racks may be placed in a commercial convection oven if 9-inch tall turkeys are being cooked, but 4 to 5 racks may be evenly spaced from top to bottom when that many racks of 2-inch tall lasagna are being cooked. Half-sized commercial convection ovens are similarly configured and dimensioned to fit into industry standard half-sized spaces in commercial kitchens and to receive industry standard half-sized sheet pans.
When cooking in a typical convection oven, heated air within the oven cavity is circulated by a fan. The fan initiates a flow of heated air by pulling air from the oven cavity through multiple openings on a back wall of the oven cavity. The heated air then exits other openings on the side walls of the oven cavity. The heated air moves through the oven cavity to help distribute heat energy to food articles placed within the oven cavity. An example of the heating system of a typical convection oven can be found in U.S. Pat. No. 4,395,233 to Smith et al.
One problem with the heating system of a conventional convection oven is that it can generate regions of high and low speed air flow in the oven cavity such that the heated air is not uniformly distributed within the oven cavity. As a result, food items placed in the oven cavity may be cooked unevenly. For example, food items placed on different racks at different heights within the convection oven may be cooked at different rates. In addition, food items placed on the same rack may not receive uniform heating either. This unevenness of cooking can result in food waste, as food items located in the higher heat portions of the oven cavity can be unacceptably overdone as compared to the food items located in the lower heat portions. Unevenness of cooking can be partially overcome by rotating cook trays within the oven cavity, as well as utilizing reduced cooking temperatures and blower speeds, but doing so will increase skilled labor requirements as well as cook times.
Conventional convection ovens have other problems as well. For example, only one cook temperature and heat transfer profile, such as blower speed, can be delivered in a conventional convection oven at any one time, thereby limiting the types of foods that can be cooked simultaneously. This can be overcome by having multiple convection ovens set at different cook temperatures and heat transfer profiles, but doing so will result in space and energy inefficiency.
Consequently, it would be desirable to provide an improved convection oven that can eliminate the above-mentioned problems.